The assembly of system components, for example, of computers and the like, can be slow and costly where threaded fasteners are commonly used. Clip fasteners may be used to expedite assembly operations, but the resulting assembly has the appearance and feel of cheap or shoddy construction because it is shiftable due to the loose tolerances that are required to accommodate the fasteners. One such type of fastener is a mushroom-headed clip where the umbrella of a round and deformable mushroom head collapses under compressive forces while the head passes through a hole. The head then expands on the backside of the hole, but the clip is permanently attached such that the clip and assembly cannot be easily detached for maintenance operations without damaging the clip or the components. Withdrawing the clip is akin to removing a barbed arrow from something into which the arrow was shot or inserted.
Clip fasteners may expedite assembly operations, but the assembled components problematically shift in position relative to one another. For example, a fan housing that is squarely connected to a computer chassis may shift relative to the computer chassis, such that the alignment between the fan housing and the chassis is no longer square. Even though the fit is sloppy, the clip fasteners are difficult or impossible to remove.
The clip fastener according to the present invention overcomes the problems that are outlined above and advances that art by providing a clip fastener that is quick and easy to attach for permanent fastening uses, yet is stable in the sense of forming a rigid coupling and is selectively detachable.
The clip fastener includes a base and a clip head. An elongate clip neck connects the base with the clip head. The clip head includes a barb having a rounded outer surface that increases in diameter towards the base. The clip neck has sufficient resilience under compressive forces exerted on the rounded outer surface of the barb, e.g., by virtue of contact with the inner surface of a hole into which the clip head is being inserted, to bend the clip neck with associated movement of the barb for clip insertion purposes. The barb or clip head may also deform to accommodate insertion.
In some embodiments, by way of example, the rounded outer surface of the barb has a semi-frustoconical shape with a flattened rear surface. The clip neck may have a semicircular cross-section with a flattened side aligned with the flattened rear surface to facilitate bending movement in an oriented direction.
The base may contain an aperture through which the clip neck extends to provide additional support from the rear surface of the clip neck. The base may comprise a block, and the barb may be oriented for bending motion diagonally across the block to obtain maximum lateral stability from the dimensions of the block. The base may be formed as part of an individual or stand-alone clip, or integrally formed into one of the components, such as an integrally formed part of a fan carrier. A plurality of clip fasteners, such as those formed into a fan carrier that has the general shape of a parallelogram, may be placed in diagonal alignment across the parallelogram such that the respective bending moments of the individual clip fasteners are each diagonally opposed to a corresponding clip fastener.
The clip fastener may be used in a method of fastening components to one another. The method includes the steps of positioning a first component having the clip fastener adjacent a hole for receipt of the clip fastener in a second component; and establishing compressive forces on the barbed tip by the action of the hole on the barb tip. The compressive forces are sufficient to bend the clip neck for passage of the barbed tip through the hole. Passing the barbed tip through the hole to establish a clip connection between the barbed tip and the second component completes insertion of the clip fastener, which may be selectively detached by manually manipulating the barb to disengage it from the second component for subsequent withdrawal from the hole.
The clip fastener may include a first object, such as a base plate, fan housing, or any other type of manufactured component, which incorporates a resilient male member having a barb. A second such object includes any complimentary receiving structure, such as a nib, hole or slot, for receiving the resilient male member to establish clipped interengagement between the first object and the second object. The resilient male member has a clip neck that flexes with corresponding movement of the barb. The barb has a head with an abutment surface, e.g., as a ramp, that abuts the complimentary receiving structure during insertion of the male member with resultant transfer of forces to flex the clip neck until clipped interengagement is established. The interengagement between the resilient male member and the complimentary receiving structure is established by the resilient male member snapping into a resting position upon loss of contact between the abutting means and the receiving means when the resilient male member is fully inserted into the complimentary receiving structure.